高频刺激左心房引起家兔慢性心房颤动

Establishment of a rabbit chronic atrial fibrillation model with long-term rapid atrial stimulation

目的:探讨以高频率起搏刺激左心房建立家兔慢性心房颤动模型的方法。方法:20只家兔随机分为实验组及对照组,对照组为假手术组,植入起搏器但不起搏,实验组10只家兔予开胸植入高频率起搏器(1000次/分)刺激左心房30d,术后定期监测起搏、心房颤动的发生情况、房颤时心室率变化,同时测定起搏前及房颤发生后心房有效不应期(AERP)的变化。结果:实验组均完成了实验,术后第7d,7只(70%)兔发生了房颤,2周时共有8只(80%)发生了房颤并能稳定维持(与对照组比较,P<0·01),30d时仍示房颤,其余2只兔至30d时仍呈起搏心律,对照组则未发生任何心律失常情况。心房颤动时的心室率最初明显增快(P<0·05),随后有所降低(P<0·05),但仍高于基础心室率(P<0·05)。AERP缩短,AERP频率适应不良,与基础状态相比有显著意义。结论:长期高频率起搏刺激家兔左心房是建立慢性房颤模型的有效方法。

AIM： The aim of this study was to investigate the possibility of establishing a chronic atrial fibrillation model with long-term rapid atrial stimulation （ 1 000 bpm）, which was performed in rabbits /n vivo. METHODS：20 rabbits were randomly divided into 2 groups： 1） control group （ n = 10）： pacemaker was implanted but no pacing; 2） experimental group （ n. = 10） ： a left intercostal thoracotomy was performed and the pericardium was opened to expose the heart and a steel - wire pacing electrode was fixed on the epicardium of the left atria in 10 rabbits. Then the rapid pulse generator was implanted subcutaneously in the left abdominal region and rapid atrial pacing （ 1 000 beats/min） was initiated and continued for 30 days. Electrocardiogram （ECG） was monitored and recorded on day 1, 3, 5, 7, 14, 21 and 30. The atrial effective refractory period （AERP） was measured before pacing and at the time of fibrillation. RESULTS： On day 14, atrial fibrillation was developed in 8 rabbits （80%） and sustained at least till to day 30 （P 〈 0.01 ）. There was no atrial fibrillation occurred in control group. The ventricular rate of atrial fibrillation was fast initially （P 〈 0.05） and decreased gradually later （P〈 0.05）. The AERP was shortened and the rate adaptation of AERP was lost when atrial fibrillation occurred. CONCLUSION： Long- term rapid left atria stimulating is an effective method in the establishment of a chronic atrial fibrillation model in rabbits.